Activation Energy Rechargeable Prussian Yellow Nano Film Electrode using Hydrated Ions

Abstract

Aim: Interfacial charge transfer is a fundamental issue in both the science and technology of the batteries. In this work, the activation energy for the interfacial charge transfer, Ea, though PY thin film was estimated by measurement measurements of electrochemical impedance spectroscopy (EIS) for both monovalent and multivalent hydration cations: Li+, Na+, K+, Ca+2 and Mg+2 in aqueous electrolytes. Background: Rechargeable batteries have become quintessential energy conversion devices that are widely used in portable electronic devices and hybrid electric vehicles. PB and its analogues have open channels that allow rapid insertion/extraction of different cations and that lead to a long cycle of its in such as batteries (Na+, Li+ and K+). Objective: preparation of Prussian yellow Nanofilm on ITO glass by a simple chemical facial method and study of its charge/discharge processes of intercalation compounds in rechargeable features. Methods: The electrochemical measurements of potentiostat/galvanostat cyclic voltammograms and EIS were carried out in three-electrode cells, with Ag/AgCl as a reference electrode. Pt. and ITO|PY as working and counter electrodes respectively. The electrolytes were solutions of 0.1 M+z cation in water where M+z was one of the following cations: Li+, Na+, K+, Ca+2 or Mg+2. Results: The effect of hydration on the activation energy for the PY thin film was studied by the EIS at different temperatures. The ions K+ have an activation energy interfacial, which is lower than that of Na+ and Li+. So the coulombic repulsion at the interface is largely suppressed by the screening effect of ions hydration, explaining the small values of Ea with aqueous electrolyte. Furthermore, the hydration helped the Ca+2 and Mg+2 intercalation in PBA but with large values of Ea that were due to coulombic repulsion at the interface. Conclusion: Prussian blue can be considered among the most promising cathode materials for energy storage batteries because of their rigid open framework with large interstitial sites that can pertain to mono and bivalent cation mobility and accommodate volume variation during ions insertion/ extraction.